Strongly Postive AO Recently
By Justin Poublon
February 10, 2020 - 8:54 AM CST | 296 2
The atmosphere is very complex and dynamic with many factors. One of the major players, the arctic oscillation over last two months has been strongly (+) positive AO. This tends to keep the polar jet stream constrained into a "donut" over the northern hemisphere.
This means that arctic cold often stays bottled up. Wisconsin still gets typical winter but the super cold shots are typically short lived. Jet stream flow is relatively faster more progressive west to east.
The opposite (-) negative AO would tend to bring more major arctic cold bursts into the lower 48, more major storms like 2018-2019, and all around more craziness. I dont know where the AO will go in the next few months but it's normal for this oscillation to cycle through phases, back and forth between + & - on many times and scales. As I mentioned 18-19' were more negative. Hopefully this helps explain the weather lately!